DE 43 01 160 A1 discloses a system for operator detection, in which in the driver's seat and in the front passenger's seat as well as in at least one operator control element there are electrical coupling elements which close a transmission path for an electrical signal via the person located on the respective seat when the operator control element is touched. The electrical signal is fed to an evaluation circuit and it is detected there whether the driver or the front seat passenger has touched the operator control element. In one embodiment, the differentiation between the persons is effected by means of different frequencies, for example 20 and 25 kHz, which are applied to the coupling element in the vehicle seats by means of signal generators. A keypad, a lever and a telephone receiver are considered to be operator control elements and it is proposed that the operator control elements have sensor faces which, when activated, are touched by the operator in a conductive fashion. However, DE 43 01 160 A1 does not contain any more detailed considerations of the way in which the sensor faces are embodied.